我想要获得一周。从以下方式的日期开始:
DatePart("WW", "30/12/2014", vbMonday, vbFirstFourDays)
但是,它将结果设为1,是否应该将结果设为53? vbMonday和vbFirstFourDays在这方面的作用是什么?
答案 0 :(得分:1)
这是因为 DatePart 功能不能根据 ISO-8601标准进行计算。
您需要这样的自定义函数来检索正确的周数和相应的年份:
Public Function ISO_WeekYearNumber( _
ByVal datDate As Date, _
Optional ByRef intYear As Integer, _
Optional ByRef bytWeek As Byte) _
As String
' Calculates and returns year and week number for date datDate according to the ISO 8601:1988 standard.
' Optionally returns numeric year and week.
' 1998-2007, Gustav Brock, Cactus Data ApS, CPH.
' May be freely used and distributed.
Const cbytFirstWeekOfAnyYear As Byte = 1
Const cbytLastWeekOfLeapYear As Byte = 53
Const cbytMonthJanuary As Byte = 1
Const cbytMonthDecember As Byte = 12
Const cstrSeparatorYearWeek As String = "W"
Dim bytMonth As Byte
Dim bytISOThursday As Byte
Dim datLastDayOfYear As Date
intYear = Year(datDate)
bytMonth = Month(datDate)
bytWeek = DatePart("ww", datDate, vbMonday, vbFirstFourDays)
If bytWeek = cbytLastWeekOfLeapYear Then
bytISOThursday = Weekday(vbThursday, vbMonday)
datLastDayOfYear = DateSerial(intYear, cbytMonthDecember, 31)
If Weekday(datLastDayOfYear, vbMonday) >= bytISOThursday Then
' OK, week count of 53 is caused by leap year.
Else
' Correct for Access97/2000+ bug.
bytWeek = cbytFirstWeekOfAnyYear
End If
End If
' Adjust year where week number belongs to next or previous year.
If bytMonth = cbytMonthJanuary Then
If bytWeek >= cbytLastWeekOfLeapYear - 1 Then
' This is an early date of January belonging to the last week of the previous year.
intYear = intYear - 1
End If
ElseIf bytMonth = cbytMonthDecember Then
If bytWeek = cbytFirstWeekOfAnyYear Then
' This is a late date of December belonging to the first week of the next year.
intYear = intYear + 1
End If
End If
ISO_WeekYearNumber = CStr(intYear) & cstrSeparatorYearWeek & Format(bytWeek, "00")
End Function
检查周数:
Public Function ISO_WeekNumber( _
ByVal datDate As Date) _
As Byte
' Calculates and returns week number for date datDate according to the ISO 8601:1988 standard.
' 1998-2000, Gustav Brock, Cactus Data ApS, CPH.
' May be freely used and distributed.
Const cbytFirstWeekOfAnyYear As Byte = 1
Const cbytLastWeekOfLeapYear As Byte = 53
Dim bytWeek As Byte
Dim bytISOThursday As Byte
Dim datLastDayOfYear As Date
bytWeek = DatePart("ww", datDate, vbMonday, vbFirstFourDays)
If bytWeek = cbytLastWeekOfLeapYear Then
bytISOThursday = Weekday(vbThursday, vbMonday)
datLastDayOfYear = DateSerial(Year(datDate), 12, 31)
If Weekday(datLastDayOfYear, vbMonday) >= bytISOThursday Then
' OK, week count of 53 is caused by leap year.
Else
' Correct for Access97/2000 bug.
bytWeek = cbytFirstWeekOfAnyYear
End If
End If
ISO_WeekNumber = bytWeek
End Function
答案 1 :(得分:0)
DatePart("ww", <Date>, vbMonday, vbFirstFourDays)
在大多数情况下会正确计算ISO 8601周数。
https://en.wikipedia.org/wiki/ISO_week_date#First_week:
第01周的ISO 8601定义是格里高利年度第一个星期四的一周。
基于本周属性的以下定义是相互等效的,因为ISO周从星期一开始:
*这是1月份的大部分时间(4次或更多次)的第一周 *等。
2015-01-01是星期四,所以是2015年第1周。
2014-12-29至2014-12-31也是2015年第1周。